At the top of the coils is a manifold, the hot air being forced through small holes to circulate in and around a regulation perforated roasting cylinder; the vapors and spent air are then drawn into an overhead exhaust pipe that connects with a pipe provided with a fresh-air intake, the idea being to return them to the roasting cylinder after being mixed with fresh air and heated in the coils as before.

While IUDs, also known as coils, are unlikely to be recommended as way of preventing cervical cancer -- the second most common form of cancer in women worldwide -- the research should reassure women and their doctors that using them carries no added risk of the disease.